Clip sensor device for measurement of vital signs

ABSTRACT

A clip sensor device for optical measuring vital signs of a subject is provided. The clip sensor device includes a internal supporting frame formed from an elongated plate configured to be folded into a desired orientation. A measuring probe is mounted on an upper surface of the frame. The measuring probe comprises a transmitter and receiver and configured for generating a time response of the blood perfused body tissue to the applied optical signal that is indicative of the vital signs of the subject. The clip sensor device also includes a pressing member mounted on the upper surface of the internal supporting frame. The pressing member includes one or more spring elements configured to provide a predetermined pressure on the blood perfused body tissue due to the deformation of the spring elements when said portion of blood perfused body tissue is applied against the pressing member.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/601,157, filed Feb. 21, 2012, which is incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

This invention relates to medical techniques for monitoring vital signs,and in particular, to a device for measuring vital signs by detectinglight transmitted or reflected from a blood perfused body tissue.

BACKGROUND OF THE INVENTION

It is well known in the art to use light transmitted through orreflected from a medium in order to determine characteristics of themedium. For example, in the medical field, where non-invasivephysiological monitoring of vital signs of a patient is often required,light transmitted through a portion of the body, and reflected orscattered from the body surface may be measured to determine informationabout the patient.

For example, during surgery, blood pressure, heart rate, breathing rateand blood oxygen saturation are often monitored. Moreover, for someindividuals, there may be a daily, even hourly need to measure suchparameters to know the individuals health and/or to detect and treatsome diseases.

Furthermore, information about vital signs can also be important toindividuals involved in athletic training and physical exercising. Forexample, one of the important applications related to physical activityis continuous heart rate monitoring. This field still requiresdevelopments in a sense that a suppressive majority of nowadays opticalsensors performing heart rate monitoring must be attached to body parts,which is inconvenient as well as relatively unreliable, mainly due tothe dependency on motion-artifacts. Other kinds of related applicationsare related to blood pressure monitoring, oximetry, breathing ratemonitoring, etc. Accordingly, the most common requirement for all of thecorresponding monitoring devices is the ability to be stable, compact,sensitive and reliable under operation with batteries.

A number of optical monitoring techniques have been proposed in the artthat use light as an optical signal transmitted through a medium, suchas a portion of a blood perfused body tissue with the goal ofdetermining vital signs. Generally, such a monitoring system (also knownas a photoplethysmograph) includes a transmitter utilizing a probeclipped on a part of the body (e.g., a finger, forehead, ear pinna or anearlobe) that includes an optical source, e.g., a light emitting diode(LED) or a laser, for irradiating the body part with light placed on oneside of the of the body part while a photodetector is placed on anopposite side of the body part.

The monitoring system also includes a receiver utilizing an opticalphotodetector (e.g., a photo diode) positioned in an optical path sothat it has a field of view which ensures the capture of a portion ofthe light which is transmitted, reflected or scattered from the bodypart. The optical detector converts the light (i.e., optical signal)into an analog electrical signal, which is subsequently amplified andprovided to an analyzer to retrieve information that was present in theoptical signal.

An example of the medical monitoring device using light transmittedthrough a portion of the blood perfused body tissue is a pulse oximeter.Pulse oximetry is used to determine the oxygen saturation of arterialblood. Oxyhemoglobin mainly absorbs infrared light while deoxyhemoglobinmainly absorbs visible red light. Accordingly, pulse oximeter devicestypically contain two types of light sources, either light emittingdiodes or laser diodes, operating in the red band of light and in theinfrared band of light, respectively. Pulse oximeter devices alsoinclude photo-detectors for each of above mentioned wavebands and theprocessing unit that detects the ratio of red/infrared absorption andcalculates the patient's oxygen saturation of arterial blood.

Specifically, transmission of optical energy as it passes through thebody is strongly dependent on the thickness of the material throughwhich the light passes, or the optical path length. Many portions of apatient's body are typically soft and compressible. Therefore, when thepatient moves, the thickness of material through which optical energypasses can change. This results in the changes of the optical pathlength. For example, if optical energy passes through a finger and theuser of an optical device moves in a manner which distorts or compressesthe finger, the optical path length changes. Changes in the optical pathlength together with the changes of venous blood movement through duringmotion can produce enough distortion in the measured signal to make itdifficult or impossible to determine desired information.

For example, U.S. Pat. Appl. Pub. No. 2009/0227853 describes an ear hookplethysmography (PPG) sensor and/or pulse oximetry (SpO₂) sensor thatcan be attached to the skin in the regions of superficial artery andvein and posterior auricular artery and vein around the ear. Forexample, an ear wearable heart rate monitor can be constructed withthese sensors.

U.S. Pat. No. 5,551,423 describes a pulse oximeter probe in the form ofa clip that can be attached to an earlobe. The probe includes a pair ofholding members that can be connected together at an end in such a waythat they can pivot on a shaft. The holding members are arranged with alight-emitting device and a light-receiving device, in such a way thatthey are in a face-to-face relationship. The shaft is fitted with a leafspring that urges the light-emitting and light-receiving devices topivot in a direction in which they approach each other. The probe can beattached to an earlobe of a subject by holding the earlobe with theholding members.

It was noted that such an oximeter probe of the clip type has two majordrawbacks. First, the holding members have to compress the earlobe so asto detect the pulsation of blood flowing in the compressed area but,then, the quantity of blood circulation decreases to lower the precisionof measurement. Second, the probe which is attached to the earlobe isliable to movements and, hence, errors due to the movement of theearlobe are most likely to occur if measurements are done while thesubject is walking.

To avoid these drawbacks, U.S. Pat. No. 5,551,423 providing a clip pulseoximeter probe that can be attached to the ear of a subject withoutcompressing the site of measurement, and that is less sensitive tounwanted movements of the neck. The probe includes a pair of holdingmembers pivotable on a shaft and configured for holding the basal partof the earlobe of a subject. The probe also includes a measuring sectionthat consists of the light-emitting and light-receiving elements whichare provided on the respective holding members in a face-to-facerelationship. The compressing portions which hold the basal part of theearlobe are separated in position from the measuring section. One of thetwo holding members forms a bent portion at an end that can be insertedinto the entrance to the auditory meatus, whereby the probe can besecurely attached to the ear. In operation, the pulse oximeter probedetects the pulsation of blood in a blood vessel by reception of lightat a light-receiving element after it is transmitted through a part ofthe earlobe.

SUMMARY OF THE INVENTION

Despite the known techniques in the area of measuring vital signs bydetecting light transmitted or reflected from a portion of the bloodperfused body tissue, there is a need for a novel sensor probe forrobust measurement of vital signs of a subject (e.g., human) that can beused in two related areas, such as clinical use and everyday monitoringof the subject's physical activities. In both these areas,miniaturization of the measuring devices is required in order tofabricate them wireless and cost effective, so that these measuringdevices could be deployed to a large population.

It would be advantageous to provide a stable miniature stand alonesensor for robust measurement of vital signs of the user that will beless vulnerable to motion artifacts under user's motion conditions suchas running and exercising. Moreover, it would be advantageous if thesystem will be less vulnerable to optical coupling between the user'sbody and the light source as well as between the user's body and thephoto-detector.

The present invention satisfies the aforementioned needs in the art byproviding a novel clip sensor device for measuring vital signs of asubject. Example of the vital signs include, but are not limited to aheart rate, a heart rate variability, an arterial pulse waveform, asystolic blood pressure, a diastolic blood pressure, a mean arterialblood pressure, a pulse pressure, a breathing rate, a total hemoglobincontent, and/or a blood oxygen saturation, etc. The clip sensor deviceincludes an internal supporting frame formed from an elongated plateconfigured to be folded into a desired orientation. When desired, theinternal supporting frame can include two plates connected by a wire orplurality of wires configured to be folded into a desired orientation.

A measuring probe mounted on the upper surface of the internalsupporting frame and comprising a transmitter and receiver. Thetransmitter is configured for generating an optical signal and emittingthe optical signal outwardly away from the upper surface of the internalsupporting frame towards a portion of blood perfused body tissue of thesubject. The receiver is configured for receiving light originated fromthe portion of blood perfused body tissue and generating a photo currentsignal including a time response of the blood perfused body tissue tothe applied optical signal. The time response is indicative of the vitalsigns of the subject.

The clip sensor device also includes a pressing member mounted on theupper surface of the internal supporting frame. The pressing membercomprises one or more spring elements configured to provide apredetermined pressure on the portion of the blood perfused body tissuedue to the deformation of the spring element when the portion of bloodperfused body tissue is applied against the pressing member.

According to some embodiments, the internal supporting frame is formedfrom a hard and formable material suitable to hold the clip sensordevice into the desired orientation and maintain this orientation duringoperation of the clip sensor device.

According to an embodiment, the desired orientation is a U-shapedorientation.

According to some embodiments, the internal supporting frame is madefrom highly ductile and malleable metals.

According to an embodiment, the internal supporting frame is made fromaluminum.

According to an embodiment, the internal supporting frame is made fromsteel.

According to an embodiment, thickness of the internal supporting frameis in the range of about 0.3 mm to about 0.8 mm.

According to an embodiment, the measuring probe is adjacent the lefthand end of said internal supporting frame.

According to some embodiments, the transmitter includes at least oneoptical emitter. Examples of the optical emitter include, but are notlimited to, a light emitting diode (LED) and laser diode. The opticalemitter can, for example, operate in the red-near infrared spectralrange, such as 600 nm through 1350 nm.

According to some embodiments, the receiver includes at least oneoptical detector. Examples of the optical detector include, but are notlimited to, a PN photodiode, PIN photodiode, avalanche photodiode (APD),phototransistor, photothyristor, photomultiplier tube (PMT).

According to some embodiments, the transmitter and receiver are bothmounted on the upper surface of the internal supporting frame adjacenteither the right hand end or the left hand end of said internalsupporting frame.

According to some embodiments, the transmitter is arranged at one end ofthe internal supporting frame, whereas the receiver is arranged atanother end of the internal supporting frame.

According to some embodiments, the spring element(s) have a non-Hookedeformation behavior so that the extension or contraction of the springelement(s) does not have a linear dependence on the load applied to it.

According to some embodiments, the spring element(s) provide(s) asubstantially constant force reaction when subjected to stress.

According to some embodiments, the spring element(s) include(s) a padmade from polyester foam or ribbon.

According to some embodiments, the spring element(s) include(s) aconical spring.

According to some embodiments, the measuring probe is adjacent one endof the internal supporting frame, whereas the pressing member isadjacent the opposite end of said internal supporting frame than themeasuring probe.

According to some embodiments, the clip sensor device further includes ahousing enveloping the at least the measuring probe by a coveringsleeve, thereby to protect the measuring probe from damage.

According to some embodiments, the covering sleeve further envelopes atleast a portion of the internal supporting frame.

According to some embodiments, the covering sleeve extends from thepressing member arranged at one end of the said internal supportingframe towards another end thereof.

According to some embodiments, the covering sleeve is made of a pliablepadding material positioned on the upper and under surfaces surroundingthe portion of the internal supporting frame extending from the pressingmember until the right hand end, thereby encasing the measuring probe.

According to some embodiments, the covering sleeve includes at least onematerial selected from a soft rubber, plastic, a cloth.

According to some embodiments, the covering sleeve includes a windowarranged over the measuring probe. The window is made of a materialpermeable to the radiation generated by the emitter.

According to some embodiments, the covering sleeve includes a pluralityof V-shaped ribs arranged in the middle of the clip sensor device.

There has thus been outlined, rather broadly, the more importantfeatures of the invention in order that the detailed description thereofthat follows hereinafter may be better understood. Additional detailsand advantages of the invention will be set forth in the detaileddescription, and in part will be appreciated from the description, ormay be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carriedout in practice, a preferred embodiment will now be described, by way ofnon-limiting example only, with reference to the accompanying drawings,in which:

FIG. 1 illustrates an example of the dependency of an amplitude of a PPGsignal on a contact pressure at the measurement location;

FIG. 2 illustrates an exploded perspective view of a clip sensor devicefor optic measuring at least one vital sign of a subject, according toone embodiment of the present application;

FIG. 3 illustrates an exploded perspective view of a clip sensor devicefor optic measuring at least one vital sign of a subject, according toanother embodiment of the present application;

FIG. 4 illustrates an exploded perspective view of a clip sensor devicefor optic measuring at least one vital sign of a subject, according toyet another embodiment of the present application;

FIGS. 5A and 5B illustrate the clip sensor device according to oneembodiment of the present application in the unfolded and U-shape foldedconfigurations, correspondingly; and

FIG. 6 illustrates an example of the clip sensor device of the presentapplication attached to an earlobe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The principles and operation of the a clip sensor device for measurementof at least one vital sign of a human according to the present inventionmay be better understood with reference to the drawings and theaccompanying description, it being understood that these drawings andexamples in the description are given for illustrative purposes only andare not meant to be limiting. The same reference numerals and alphabeticcharacters will be utilized for identifying those components which arecommon in the device for measurement of at least one vital sign of ahuman and its components shown in the drawings throughout the presentdescription of the invention.

As described above, photoplethysmographic sensors are typically placedon a subject in a location that is normally perfused with arterial bloodto facilitate measurements of the desired vital signs. Aphotoplethysmographic (PPG) signal that is measured by aphotoplethysmograph is a signal produced by arterial blood volumechanges associated with periodic contractions and relaxations of theheart. A magnitude of the PPG signal is a function of the amount of theblood ejected from the heart with every systolic cycle, the opticalabsorption of blood, absorption by skin and tissue components, and thespecific wavelengths used to illuminate the vascular tissue bed. Duringdiastole, the blood volume in the vascular bed decreases, thus toincrease the amount of the light transmitted or backscattered.

It should be noted that the reliability of the photoplethysmographicmeasurements depend on the contact pressure of a photoplethysmographicsensor on a measurement location. When the contact pressure used tosecure the sensor to the measurement location on the body is too low,then distorted PPG waveforms can be generated, that results ininaccurate measurements. On the other hand, if the contact pressure istoo high, then the blood circulation can be compromised or even necrosiscan occur when the sensor is worn for extended periods of physicalactivity. When a blood circulation is slow, the ability to measure Sp0 ₂is also reduced. Moreover, when a too large contact pressure is used, acomplete vessel occlusion can occur, that may lead to a complete loss ofthe PPG signal and jeopardize the ability to obtain Sp0 ₂, HR and othervital sign data from the measurements. The optimal contact pressure willresult in the greatest AC amplitudes and SNR will be the highest, whichmay result in improved measurement accuracy.

Referring to FIG. 1, an example of the dependency of an amplitude of aPPG signal on a contact pressure at the measurement location (such as afinger) is shown. The PPG amplitudes are normalized to the largestobserved amplitude for each individual. Each point on the graphrepresents the mean normalized amplitude for all 10 individuals. The 95%confidence intervals were calculated for each point to determine if theobserved amplitude was statistically within an optimal range, which wasdefined as pressures yielding normalized amplitudes greater than 0.7. Avalue of 0.7 was chosen as the nominal threshold because preliminarydata suggested that this would be the maximal value that could bestatistically identified without relying on extremely large samplesgreater than 150.

Regions 11 and 15 in FIG. 1 indicate contact pressures that do notprovide optimal amplitudes. Regions 12 and 14 represent instances wherethe confidence interval produced amplitude values equal or less than0.7, therefore, optimal amplitude in these regions is questionable. Aregion 13, corresponding to the pressure in the range of 60 mmHg-80mmHg, represents optimal contact pressures.

In accordance with these experimental results, the present applicationprovides a novel clip sensor device that can maintain the contactpressure at a desired magnitude. It should be note that the desiredmagnitude of the contact pressure may depend on the measurement locationon the body of a subject. For example, when the measurements are carriedout on a finger, the contact pressure can be in the range of 60 mmHg-80mmHg

Referring to FIG. 2, an exploded perspective view of a clip sensordevice 20 for optic measuring at least one vital sign of a subject(e.g., a living human) is illustrated, according to one embodiment ofthe present invention. Examples of the vital signs which can be measuredby the system of the present application include, but are not limitedto, a heart rate, a heart rate variability, an arterial pulse waveform,a systolic blood pressure, a diastolic blood pressure, a mean arterialblood pressure, a pulse pressure, a breathing rate, a blood oxygensaturation, total hemoglobin content and/or anaerobic thresholdmonitoring, etc.

The clip sensor device 20 includes an internal supporting frame 21formed, for example, from an elongated, relatively thin plate formedfrom any hard and formable materials suitable to hold the clip sensordevice in a desired orientation. It should be understood that whendesired the frame can be formed from two plates at the ends 213 and 214connected to each other by means of a wire or plurality wires. Inparticular, materials such as highly ductile and malleable metals, hardor firm plastic, and the like that can be bent into a tight U-shape andmaintain this shape during operation can be used as materials suitablefor the internal supporting frame 21. Examples of the metals suitablefor internal supporting frame 31 include, but are not limited to,aluminum, copper, gold, steel, etc. In particular, when the internalsupporting frame 21 is made of aluminum, it can have thickness in therange of 0.3 mm-0.8 mm Such provision can make the frame 21 extremelylight to minimize motion artifacts during operation of the clip sensordevice 20.

As shown in FIG. 2, the internal supporting frame 21 has an uppersurface 211, an under surface 212, right hand end 213 and a left handend 214. The terms “upper surface”, “under surface”, “right hand end”,and “left hand end” are used herein for the purpose of description of arelationship between the different parts of the internal supportingframe 21 and the clip sensor device 20, rather than for description oforientation of the sensor structure in space.

The clip sensor device 20 also includes a measuring probe 22 mounted onthe upper surface 211 of the internal supporting frame 21, adjacent theright hand end 213. According to one embodiment of the presentinvention, the measuring probe 22 comprises a transmitter 23 and areceiver 24. The transmitter 23 includes one or more optical emitters231 (only two emitters are shown in FIG. 2) configured for generating anoptical signal and emitting the optical signal outwardly away from theupper surface of the internal supporting frame 21. Generally, theemitter 231 can be a light source (e.g. visible, infrared, etc.), anultra-sonic source, a microwave source, etc. Examples of the opticalemitter 231 include, but are not limited to, emitting diodes (LEDs),laser diodes, or similar emitting devices.

Depending on the vital sign selected for determination, the opticalsources may, for example, operate all at the same light wavelength.According to another embodiment, at least one of the light sourcesoperates at a different wavelength. For example, for measurements ofheart rate, one or more light emitting sources can operate at the samewavelength that can be selected within the transparency window ofhemoglobin and water, i.e. in the red-near infrared spectral range, suchas 600 nm through 1000 nm When the monitoring of total hemoglobin istargeted this range can be expanded till 1350 nm.

For measurements of a level of oxygen saturated in blood, at least twotypes of light emitting sources operating in the red band of light andin the infrared band of light are required.

According to one embodiment of the present invention, the receiver 24includes one or more optical detectors 241 (only one optical detector isshown in FIG. 2) mounted on the upper surface 211 of the internalsupporting frame 21, adjacent the right hand end 213. The opticaldetector 241 is arranged in the vicinity of the emitters 231 andconfigured for receiving light originated from (i.e., reflected from) atleast a portion of the illuminated measurement location of the subject(not shown). In operation, the optical detector 241 generates a photocurrent signal that includes a time response of the blood perfused bodytissue to the applied optical signal. The time response is indicative ofvital signs of the subject. The optical detector 241 can include one ormore photodiodes or other photo-receiving devices positioned in anoptical path so that a field of view of the optical detector 241 ensuresthe capture of a portion of the light originated from the blood perfusedbody tissue. An example of the suitable photodiode includes, but is notlimited to, a common low-cost PN photodiode, a PIN photodiode, anavalanche photodiode (APD), phototransistor, a photothyristor, aphotomultiplier tube (PMT), etc. The receiver 24 may include anamplifier (not shown) coupled to the optical detector 241, andconfigured to convert the photocurrent generated by the optical detector241 into a voltage signal carrying the information about the vitalsigns.

As shown in FIG. 2, the arrangement of the optical emitters 231 and theoptical detector 241 with respect to the internal supporting frame 21 issuch that the system 20 can operate with reflected light. However, whendesired, the system 20 can also operate with transmitted light, mutatismutandis.

Referring to FIG. 3, an exploded perspective view of a clip sensordevice 30 for optic measuring at least one vital sign of a subject isillustrated, according to another embodiment of the present invention.The clip sensor device 30 differs from the clip sensor device (20 inFIG. 2) in the fact that one or more optical emitters 231 are mounted atthe right hand end 213 and one or more optical detector 241 is at theleft hand end 214. It can be understood that this provision of themeasuring probe enables operation with transmitted light.

The measuring probe 22 is electrically connected through a hard wiredcoupling 25 and optionally a connector 26 to external processingapparatus (not shown) that includes, inter alia, such modules as anoptical signal driver (not shown) coupled to the transmitter 23 andconfigured for generating a series of electric pulses for driving thetransmitter 23 by turning it “on” or “off”. The external processingapparatus also includes a demodulator (not shown) and a control unitconfigured for adaptive control of the operation of the measuring probe22. The processing apparatus can, for example, be associated with asuitably programmed computer system (not shown) having, inter alia, suchknown utilities as a processor, a memory unit for storing the processeddata, and a monitoring system configured for presenting the measuredresults of vital signs. The processor is preprogrammed by a suitablesoftware model capable of analyzing the received data and determiningone or more desired vital signs. The monitoring system can include adisplay, printer and/or other monitoring devices (not shown). Whendesired, the monitoring system can include an alarm system to produce ahuman detectable signal when a vital sign measurement generated by theoutput unit meets predetermined criteria. For example, the monitoringsystem can be adapted to create a visual or audio alarm to alert a userthat a detected vital sign is outside of a predetermined range. Whendesired the computer system can be associated with other computersystem, which are connected to each other through a network, forexample, through the Internet, thereby to transmit the measuredinformation about the vital signs to a desired party.

The clip sensor device 20 also includes a pressing member 27 mounted onthe upper surface 211 of the internal supporting frame 21, adjacent theleft hand end 214, however other configurations are also contemplated.According to one embodiment of the present invention, the pressingelement 27 comprises one or more spring elements 271, 272 configured toprovide a predetermined pressing force on a surface against which thepressing element 27 is applied, due to the deformations of the springelements 271, 272.

According to the present application the spring elements 271, 272 have anon-Hooke deformation behavior so that the extension or contraction ofspring elements 271, 272 does not have a linear dependence on the forceapplied to it. According to an embodiment of the present invention, thespring elements 271 provide a relatively constant (or close to constant)force reaction when subjected to stress.

One type of a device with such properties is the spring element 272,which is in the form of a pad that is made, for example, from polyesterfoam or ribbon. Another type of device with such properties is thespring element 271, which is a conical spring, although other elementshaving non-Hooke deformation behavior are contemplated. For example,FIG. 2 shows a combined spring element that includes the conical springelement 271 embedded into the pad spring element 272 made of polyesterfoam.

Referring to FIG. 4, an exploded perspective view of a clip sensordevice 40 for optic measuring at least one vital sign of a subject isillustrated, according to another embodiment of the present invention.The clip sensor device 40 differs from the clip sensor device (20 inFIG. 2) in the fact that the spring elements 271, 272, mounted at theboth ends 213 and 214 of the internal supporting frame 21, respectively.In this case, the measuring probe 22 can, for example, be arrangedwithin the pad spring element 272 or mounted on the top of the springelement 271.

FIGS. 5A and 5B illustrate the clip sensor device 20 in the unfolded andU-shape folded configurations. In operation, the internal supportingframe 21 is folded to form a generally U-shaped configuration. The clipsensor device 20 can be positioned by bending the internal supportingframe 21 over an anatomical location of the user's body (e.g., a finger,ear pinna, earlobe, lip, etc.) 51 with the blood perfused body tissue,and squeezing near the ends 213 and 214. An example of the clip sensordevice 20 attached to an earlobe 61 is shown in FIG. 6.

In operation, the clip sensor device 20 clamps the anatomical location,the pressing member 27 is pressed against a blood perfused body tissueto exert an optimal pressure thereon over the squeezing range. Accordingto some embodiments, the optimal pressure is within the range of 60mmHg-80 mmHg As described above, the application of the optimal contactpressure will result in the greatest PPG amplitudes and provide anenhance measurement accuracy.

Referring to FIGS. 2, 5A and 5B together, the clip sensor device 20 canalso includes a housing 28 enveloping the measuring probe 22. Thehousing 28 can be in the form of a covering sleeve to protect themeasuring probe 22 from damage owing to humidity, scratching, contactswith foreign objects, and other damaging factors during exploitation.When desired, at least a portion of the internal supporting frame 21 canalso be enveloped by the housing (i.e., covering sleeve) 28. As shown inFIG. 2, the covering sleeve 28 extends from the pressing member 27towards the right hand end 213. The covering sleeve 28 is made of apliable padding material positioned on the upper and under surfaces 211and 212 surrounding the portion of the internal supporting frame 21extending from the pressing member 27 until the right hand end 213,thereby encasing the measuring probe 22, and provides a conformablesurface for engagement of the clip sensor device 20 with themeasurements location of the subjects body. The covering sleeve 28 canbe made from or include, for examples, a soft rubber, plastic, (such assilicon or polyurethane), cloth and other materials. When desired, thehousing (i.e., covering sleeve) 28 can be fixed to the internalsupporting frame 21 by means of bolts, screws and or rivets (not shown)via openings 283.

According to an embodiment, the covering sleeve 28 includes a window 282arranged over the measuring probe 22 made of a material (e.g., glasscrystal) permeable to the radiation generated by the emitter 231 and tothe radiation originated from the blood perfused body tissue forcollecting by the detector 241.

According to an embodiment, the covering sleeve 28 includes a pluralityof V-shaped ribs arranged in the middle of the clip sensor device 20. Asshown in FIG. 5A, the V-shaped ribs prevent the frame from bending inV-shape and force it to bend in U-shape protecting the frame fromfolding it into V-shape. It should be understood that when a framereceives a V-shape during folding, it can be broken quicker than in thecase when the frame receives U-shape, since U-shape is less acute andcan be folded much larger times before breaking apart.

Those skilled in the art to which the present invention pertains, canappreciate that while the present invention has been described in termsof preferred embodiments, the concept upon which this disclosure isbased may readily be utilized as a basis for the designing of otherstructures, systems and processes for carrying out the several purposesof the present invention.

When desired, the clip sensor devices 20, 30 and 40 can be in the formof a jewelry ring, jewelry ear clip or any other jewelry item, and havean attractive ornamental appearance. When desired, the clip sensordevices can be decorated with gemstones, crystals and/or otherdecorating items.

Also, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of description and should not beregarded as limiting.

Finally, it should be noted that the word “comprising” as usedthroughout the appended claims is to be interpreted to mean “includingbut not limited to”.

It is important, therefore, that the scope of the invention is notconstrued as being limited by the illustrative embodiments set forthherein. Other variations are possible within the scope of the presentinvention as defined in the appended claims. Other combinations andsub-combinations of features, functions, elements and/or properties maybe claimed through amendment of the present claims or presentation ofnew claims in this or a related application. Such amended or new claims,whether they are directed to different combinations or directed to thesame combinations, whether different, broader, narrower or equal inscope to the original claims, are also regarded as included within thesubject matter of the present description.

What is claimed is:
 1. A clip sensor device for optical measuring atleast one vital sign of a subject, the clip sensor device comprising: ainternal supporting frame configured to be folded into a desiredorientation, and having an upper surface, an under surface, a right handend, and a left hand end; a measuring probe mounted on the upper surfaceof the internal supporting frame and comprising a transmitter configuredfor generating an optical signal and emitting the optical signaloutwardly away from the upper surface of the internal supporting frametowards a portion of blood perfused body tissue of the subject, and areceiver configured for receiving light originated from the portion ofblood perfused body tissue and generating a photo current signalincluding a time response of the blood perfused body tissue to theapplied optical signal, the time response is indicative of said at leastone vital sign of the subject; a pressing member mounted on the uppersurface of the internal supporting frame, said pressing membercomprising at least one spring element configured to provide apredetermined pressure on the portion of the blood perfused body tissuedue to the deformation of the spring element when said portion of bloodperfused body tissue is applied against the pressing member.
 2. The clipsensor device of claim 1, wherein said internal supporting frameincludes at least one elongated plate formed from a hard and formablematerial suitable to hold the clip sensor device into said desiredorientation and maintain this orientation during operation of the clipsensor device.
 3. The clip sensor device of claim 1, wherein saiddesired orientation is a U-shaped orientation.
 4. The clip sensor deviceof claim 1, wherein said internal supporting frame is made from highlyductile and malleable metals.
 5. The clip sensor device of claim 1,wherein said internal supporting frame is made from a metal selectedfrom aluminum, steel, copper and gold.
 6. The clip sensor device ofclaim 1, wherein the transmitter includes at least one optical emitterselected from a light emitting diode (LED) and laser diode.
 7. The clipsensor device of claim 6, wherein said at least one optical emitteroperates in the red-near infrared spectral range, such as 600 nm through1350 nm.
 8. The clip sensor device of claim 1, wherein the receiverincludes at least one optical detector selected from a PN photodiode, aPIN photodiode, an avalanche photodiode (APD), a phototransistor, aphotothyristor, a photomultiplier tube (PMT).
 9. The clip sensor deviceof claim 1, wherein said at least one optical emitter and said at leastone optical detector are both mounted on the upper surface of theinternal supporting frame adjacent either the right hand end or theright hand end of said internal supporting frame.
 10. The clip sensordevice of claim 1, wherein the transmitter is arranged at one end of theinternal supporting frame, whereas the receiver is arranged at anotherend of the internal supporting frame.
 11. The clip sensor device ofclaim 1, wherein said at least one spring element have a non-Hookedeformation behavior so that the extension or contraction of said atleast one spring element does not have a linear dependence on the forceapplied to it.
 12. The clip sensor device of claim 1, wherein said atleast one spring element provides a substantially constant forcereaction when subjected to stress.
 13. The clip sensor device of claim1, wherein said at least one spring element includes a pad made frompolyester foam or ribbon.
 14. The clip sensor device of claim 1, whereinsaid at least one spring element includes a conical spring.
 15. The clipsensor device of claim 1, wherein said measuring probe is adjacent oneend of said internal supporting frame, whereas said pressing member isadjacent the opposite end of said internal supporting frame than themeasuring probe.
 16. The clip sensor device of claim 1, furthercomprising a housing enveloping the at least the measuring probe by acovering sleeve, thereby to protect the measuring probe from damage. 17.The clip sensor device of claim 16, wherein the covering sleeve furtherenvelopes at least a portion of the internal supporting frame.
 18. Theclip sensor device of claim 16, wherein the covering sleeve extends fromthe pressing member arranged at one end of the said internal supportingframe towards another end thereof.
 19. The clip sensor device of claim16, wherein the covering sleeve includes a window arranged over themeasuring probe made of a material permeable to the radiation generatedby the emitter.
 20. The clip sensor device of claim 16, wherein thecovering sleeve includes a plurality of V-shaped ribs arranged in themiddle of the clip sensor device.